Design of Tunable Dual-Band Terahertz Metamaterial Absorber With Liquid Crystal Integrated On-Chip

Terahertz metamaterial absorbers (TMAs) have exhibited significant potential in high-speed communication, sensing, and imaging, attributed to their thin thickness and excellent wave-absorbing capabilities. However, traditional sandwich-structured metamaterial (MM) absorbers lack the tunable absorption performance once fabricated, severely limiting their applications. In this article, we propose a tunable TMA by integrating liquid crystal (LC) within the MM as a dielectric layer. By applying a bias electric field, the refractive index of the LC can be changed, thereby achieving the tunable resonant frequency. Particularly, the dual-band absorption and polarization insensitivity is accomplished through a symmetrical porous mesh structure, which can induce double magnetic dipole resonance modes, and this expands the tunable frequency range of the absorber. Simulation results show that the two resonant frequencies can be continuously tuned from 0.266 to 0.294 THz and from 0.358 to 0.394 THz, with a tunability of 9.5% and 9.1%, respectively. This novel design provides an effective method for developing tunable TMAs, holding great significance in advancing the performance of terahertz (THz) devices.